The radioisotopic footpad assay was found to be sensitive enough for detecting tumor associated antigens in non-virus-induced tumors of mice and rats. Human delayed hypersensitivity reactions to BCG and/or Varidase was adoptively transferred to X-irradiated mice with this assay. Influenza virus-augmented tumor associated antigens were successful for preventing metastasis and regrowth of tumors in mice after excision of tumors. The specific marker for rat thymus cells was discovered using the rosette formation test with guinea pig erythrocytes. The virus-augmented tumor associated antigens induced positive footpad reactions in histoincompatible tumor-bearing mice. BIBLIOGRAPHIC REFERENCES: Takeichi, N., Economou, G.C. and Boone, C.W.: Accelerated regeneration of trypsin-treated surface antigens of SV40 transformed BALB/3T3 cells attached to solid substrates. Cancer Res. 36: 94-101, 1976.